Alright, so I don't often pay attention to the ads we have on our site, but the recent batch unveiled today by ASUS couldn't be ignored. On some of them is JJ, ASUS' PR guy for motherboards and graphics cards. While the vast majority of PR people don't truly know the product they're trying to sell you, JJ tends to know more about his product than any reviewer ever will. I've had some great conversations with him in the past, and me being left uninformed was certainly not an option for him.

Here are the videos; some cool technologies offered on ASUS' X79 boards are discussed:

I noticed the ads too. The fact they pointed to youtube videos is something we don't often see. The first video I saw was exactly the Ram Cache/Disk one and decided I had to see the other. Great show there by JJ. (Despite the fact he doesn't hide his love for the word 'actually'.)

As much as I love what ASUS is doing, the SSD caching needs a great big asterisk on it. Tech Report was the first to test the Marvell controller ports, and the performance is just as bad as it was on X58 and Z68. You would see faster performance for cached data, but you'd also see write performance drop by exactly 50% for non-cached data... no thank you.

Hey guys. I just built a new ASUS X79 PC based on the performance in these videos. I do notice that the sppeds on the Marvel controller aren't as fast as on the Intel controller. I have a WD 450GB Velociraptor as my main drive and I installed a 120GB SSD (The exact model listed in the demos by Asus) for the purpose of using the SSD caching. I benchmarked the SSD and saw some weak performance issues. Using ATTO I was seeing the write speed max out at around 175MB per second and the write speeds hitting around 400MB per second max. There is a huge disparity between the 2 on the graph.

When I moved the SSD over to the Intel Controller I see much better perfomance with both read and write exceeding 500MB per second on the last few tests.

Is this a Marvel driver issue or a hardware thing?

After moving forward and setting up the SSD cache, I ran some benchmarks again and I was getting some interesting results.

The read speeds peaked in the mid 300MB range for the Raptor/SSD combo.
The write speeds peaked around 70MB through almost all of the tests. Odd.

So what are my options? Should I be concerned that my read and write speeds are so far apart and what problems can that cause? Honestly, the machine seems to be booting and loading apps pretty darn fast, but I am wondering the consequences of this setup.

Any help would be appreciated.

Also, can anyone point me to a tutorial or website with information on how to setup a "RAM cache" like the one that JJ demos in the other Asus videos? He shows the results of a "RAM cache" but never really how it is configured or what program accomplished this.

This is an old problem, unfortunately. The Marvell controller is only capable of using a PCIe 1x link, which artificially limits the port to <500MB/s. This is bad enough, but for some reason write speeds are penalized even more with the Marvell controllers, 150MB/s is actually common. Rob and I brought this issue up in this article: http://techgage.com/article/battle_o...0_controllers/

There isn't anything you can really do except to let ASUS know your displeasure with this arrangement. I was informed that the only Marvell chips capable of utilizing ASUS's SSD caching were NOT capable of accepting more than 1x links, so this problem is permanent in the hardware design of the board.

I can't speak for ASUS's SSD caching performance, but given such results I think users would be better off simply putting the SSD directly on the Intel SATA 6Gbps port. Most SATA 6Gbps SSDs are fast enough that caching is superfluous at this point.

I'm afraid that I don't know what software JJ utilized, I've been meaning to ask him but never got around to it given I don't have X79 hardware to test it on.Given the Marvell controller's <500MB/s bandwidth bottleneck, any sort of RAMdisk cache would be better off skipping the ASUS caching anyway I'd suspect.